UMM QASR, Iraq (CNN) --Seven battered trucks arrived in the port of Umm Qasr Wednesday as British Marines combing the city reportedly found a large supply of weapons in a school.

The trucks delivered about 12 tons of much-needed humanitarian aid, and the British army handed out rice, water and other essentials to Iraqis who had not eaten for several days.

British Royal Marines found three classrooms full of grenades, rocket-propelled grenades and Iraqi military uniforms at the school during house-to-house searches, a British pool correspondent reported. The Marines also arrested a number of people during the searches.

Saddam Hussein has long been accused of hiding weapons in civilian buildings, such as mosques, hospitals and schools.

The uniforms may indicate the estimated 120 Iraqi troops who had been there discarded their military clothes and "melted away into the civilian population," the pool reporter said.

Until the threat of war closed the port, two-thirds of the food that fed two-thirds of the Iraqi people under the United Nation's "Oil For Food" program came into Umm Qasr. (Full story)

The delivery Wednesday highlighted the problems of feeding a hungry civilian population as war rages.

The shipment immediately went into storage for later distribution, and even the amount delivered had been limited for weather and security concerns.

Illustrating the difficulty of the humanitarian aid mission, the planned convoy of 30 trucks was cut to seven as the shipment of water and food packets rumbled out of Kuwait City in a blinding sandstorm.

The convoy of donated Kuwaiti food and water was escorted across the border by the U.S. military.

Adding to the problems, Umm Qasr, Iraq's most important port and the gateway for most of the country's food, was not fully secured.

British Marines were patrolling and clearing areas one by one, while dolphins, divers and explosive experts from three countries struggled to give the port and its waters a clean bill of health. (Dolphins hunt mines)

The British officer in charge of restoring the port to operational status, Lt. Col. Paul Ash, said he hoped the first ship would be able to dock Thursday. He said his biggest needs were running water and electricity, and the return of port workers to their jobs.

Over time, military chiefs want to see the humanitarian effort gradually turned over to aid agencies. Some agencies object to working alongside the military, however, arguing it endangers all concerned and that the mission should be taken on only by the U.N..

A British Royal Marine helps distribute water and aid in Umm Qasr.

Security Council members cited progress Wednesday toward creating a resolution to provide immediate short-term humanitarian relief to Iraq and said they expect agreement on a text soon.

German U.N. Ambassador Guenter Pleuger said: "We have to act quickly. Eighty percent of the food basket in Iraq depends on oil-for-food, and 60 percent of the population depends 100 percent on oil-for food."

Secretary-General Kofi Annan asked the council to reconfigure the oil for food program so the world body can take it over from the Iraqi government -- and thus be given the authority to change or negotiate contracts.

The proposal sparked criticism from the still-standing Iraqi government and raised concerns the move would imply U.N. approval for the war and a subsequent occupation. The United States said the U.N. role would be temporary.

Meanwhile, aid groups were especially concerned about Iraq's children. Those under 15 make up almost half the Iraqi population, and they were vulnerable, even before the war, said Sonia Khush from the Save the Children charity.

"Children are going to be completely psychologically traumatized by the situation they're facing right now," she told CNN in Kuwait City, where her group was preparing to offer aid.